a rancher intends to fence off three sides of a rectangular region along a straight stretch of the river (no fence along the river). The enclosed...

a rancher intends to fence off three sides of a rectangular region along a straight stretch of the river (no fence along the river). The enclosed area is to be 1800 square meters. let x represent the lengths of sides that are perpendicular to the river. If F represents the total length of fencing material needed, write F as a function of x.